An updated thunderbird package that fixes several security issues is nowavailable for Red Hat Enterprise Linux 4 and 5.

The Red Hat Security Response Team has rated this update as having criticalsecurity impact. Common Vulnerability Scoring System (CVSS) base scores,which give detailed severity ratings, are available for each vulnerabilityfrom the CVE links in the References section.

Several flaws were found in the processing of malformed HTML content. AnHTML mail message containing malicious content could possibly lead toarbitrary code execution with the privileges of the user runningThunderbird. (CVE-2011-0080)

An arbitrary memory write flaw was found in the way Thunderbird handledout-of-memory conditions. If all memory was consumed when a user viewed amalicious HTML mail message, it could possibly lead to arbitrary codeexecution with the privileges of the user running Thunderbird.(CVE-2011-0078)

An integer overflow flaw was found in the way Thunderbird handled the HTMLframeset tag. An HTML mail message with a frameset tag containing largevalues for the "rows" and "cols" attributes could trigger this flaw,possibly leading to arbitrary code execution with the privileges of theuser running Thunderbird. (CVE-2011-0077)

A flaw was found in the way Thunderbird handled the HTML iframe tag. AnHTML mail message with an iframe tag containing a specially-crafted sourceaddress could trigger this flaw, possibly leading to arbitrary codeexecution with the privileges of the user running Thunderbird.(CVE-2011-0075)

A flaw was found in the way Thunderbird displayed multiple marqueeelements. A malformed HTML mail message could cause Thunderbird to executearbitrary code with the privileges of the user running Thunderbird.(CVE-2011-0074)

A flaw was found in the way Thunderbird handled the nsTreeSelectionelement. Malformed content could cause Thunderbird to execute arbitrarycode with the privileges of the user running Thunderbird. (CVE-2011-0073)

All Thunderbird users should upgrade to this updated package, whichresolves these issues. All running instances of Thunderbird must berestarted for the update to take effect.

4. Solution:

Before applying this update, make sure all previously-released erratarelevant to your system have been applied.